Multiple engine output equalizing apparatus



Feb. 22, 1949.

A. G. LARSON MULTIPLE ENGINE OUTPUT EQUALIZING APPARATUS 2 Sheets-Sheet 1 Filed March 5, 1946 INVENTOR Arthur Glarson dTTORNE Y Feb. 22, 1949.

A. G., LARSON MULTIPLE ENGINE OUTPUT EQUALIZING APPARATUS 2 Sheets-Sheet 2 Filed March 5, 1946 INVENTOR Arthur G. Larson dTTORNEY Patented Feb. 22, 1949 UNITED STATES ATENT GFFICE MULTIPLE ENGINE OUTPUT EQUALIZING AIPARATUS Application March 5, 1946, Serial No. 652,151

Claims. 1

This invention relates to control apparatus and more particularly to means for equalizing the power output of a plurality of prime movers such as internal combustion engines of the Diesel type.

In the copending application of James A. Campbell, Serial No. 654,931 filed March 16, 1946, and assigned to the assignee of the present application, there is disclosed a control system for a plurality of prime movers arranged to be controlled and operated in unison. The system embodies apparatus on one of the prime movers which is preconditioned to control apparatus on the other prime mover or prime movers to automatically cause operation of said other prime mover or movers to produce the same power output as from the one prime mover. In case the control apparatus on the one prime mover, which may be called a master, should fail however, or if for any reason the master prime mover should become inoperative, and it was desired to still operate the other prime movers, the power output of said other prime movers would not and could not be automatically equalized.

The principal object of the invention is therefore the provision of an improved control system for a plurality of prime movers, arranged to be operated in unison, in which any one of the prime movers can be selected to act as the master for causing equalization of the power output of all of the prime movers.

Other objects and advantages will be apparent from the following more detailed description of the invention.

In the accompanying drawings; Fig. l is a diagrammatic view of control apparatus for controlling the speed or power output of a plurality of prime movers and embodying the invention; Fig. 2 is a diagrammatic view of a portion of a fuel control system for each of said prime movers; Fig. 3 is a sectional view of a power or governor control motor for each of said prime movers and shown in elevation in Fig. 1; Fig. 4 is a sectional View of a pressure regulating valve device for each of said prime movers and shown in elevation in Fig. l; and Fig. 5 is a sectional View of an equalizing Valve device for each of said prime movers and shown in elevation in Fig. 1.

Description As shown in Fig. l of the drawings, the dotdash line enclosures, designated A and B, indicate two of any desired number of prime movers which it is desired to control and operate in unison. Each of the prime movers may, for the purpose of illustration, be of conventional Diesel engine type comprising a cam shaft I (Fig. 2) for operating, through a cam 2 and a push rod 3, a fuel injector pump 4 for supplying fuel through an injector pipe 5 to a cylinder (not shown) of said engine. The amount of fuel supplied to the engine cylinder by pump t is adapted to be regulated by a pump adjusting rack E; which is operatively connected to a lever l on a fuel control shaft 8. The fuel shaft 3 may have an engine idling position in which it is shown in the drawing for adjusting pump t to provide fuel to the engine cylinder in an amount sufficient to cause operation of the engine at an idling speed, and may be turned in a clockwise direction, as viewed in Figs. 1 and 2, to adjust said pump to increase the fuel supply in proportion to the degree of such turning. A maximum amount of fuel will be provided to the engine cylinder in a position of the fuel control shaft 8 such as indicated by a dot-dash line 9. It will be understood that each engine may have any desired number of cylinders and that a fuel pump 4, rod 3 and cam 2 will be provided for each cylinder, and that the fuel shaft 8 will be connected to all of said pumps in accordance with conventional practice.

Adjustment of the fuel control shaft ii on each engine may be controlled by a speed governor it which may comprise a centrifuge i 1 connected by gears I la to the cam shaft l. Two oppositely arranged centrifugally controlled governor arms in the form of bell cranks l2 are pivoted at their knees on pins l3 in centrifuge ll. One end of each of the bell cranks l2 engages a collar H5 sccured to a vertically movable plunger or rod it which is provided with another collar l6 engaged by one end of a governor control spring 2?. The opposite end of spring ii is engaged by a movable follower it against which bears an adjusting cam l9 pivoted on a fixed pin 25 and connected by an arm 2| to a governor adjusting rod 2'2.

When the engine is in operation turning cam shaft l centrifugal force of the governor bell cranks l2 will be opposed by the pressure of the control spring ll, and the upper end of said cranks will move away from rod 55 to a position in which said centrifugal force will balance the pressure of said spring, to thereby position said rod in accordance with the pressure of said spring. If the cam i9 is turned in a counterclockwise direction (Fig. 2) to increase the pressure of spring H on collar it the upper ends of bell cranks I2 will be moved toward rod E5 to permit said rod to move down a proportional degree, while, if the cam is returned toward the position in which it is shown in the drawing, the rod l5 will be ele- "vated correspondingly. In other words, when the engine is operating the rod l5 will assume a position corresponding to the adjustment of cam l9.

An operating arm 23 on the fuel control shaft 8 is connected by a link 24 to one end of a lever 25. The opposite end of lever 25 is fulcrumed on a fixed pin 25, while intermediate its end said lever is connected by pin 21 to the governor rod [5, whereby the fuel control shaft 8 will be positioned in accordance with the position of said rod and of cam [9.

In the drawing the parts of governor ID including cam l9 and the fuel control shaft 8 are shown in positions which it may be assumed will provide for operation of the engine at an idling speed. If the cam I9 is turned from this idling position in a clockwise direction, the governor rod i5 and fuel control shaft 8 will move out of idling position to a new position, corresponding to the change in position of said cam, to cause a proportional increase in the amount of fuel supplied to the engine and thereby a corresponding increase in power output of the engine. Turning of cam i9 in the opposite direction will result in a corresponding reduction in the amount of fuel suppiled to the engine. It will thus be seen that by suitable adjustment of cam E9 the supply of fuel to the engine may be adjusted to obtain any selected degree of power output from the engine. At each engine the governor control rod 22 is operatively connected to a fluid pressure controlled power or governor control motor '28 which is arranged to control the respective speed governor I El.

Each of the fluid motors 28 comprises (Fig. 3) a casing containing a flexible diaphragm 29 clamped around its edge in the casing and having at one side a pressure chamber 30 connected to a pipe 3 I. At all of the engines the pipes 3! are connected to a common control pipe 32 leading to an operators control valve device 33 which may be of any suitable structure for varying the pressure of fluid in said control pipe and thereby in pressure chambers 30 in the governor control motors 28 at all of the engines, simultaneously. At the opposite side of diaphragm 29 in each of the governor control motors 23 is a non-pressure chamber 34 which is in constant communication with atmosphere through a passage 35. An operating rod 36 disposed in non-pressure chamber 54 extends through the center of diaphragm 29. The rod 36 is provided in non-pressure chamber 34 with a follower 31 engaging the adjacent face of diaphragm 29, while mounted over said rod in pressure chamber 39 is a follower 38 and a clamping nut 39 having a screw-threaded engagement with said rod for clamping said followers and thereby said rod to the central portion of said diaphragm. In each motor 28, the rod 36 extends to the exterior of the casing through a bore provided in a regulating nut 65 which extends into nonpressure chamber 3% for supporting one end of a regulating spring GI. The spring 4| encircles rod and its opposite end bears against the follower 3? forming a part of said rod. The end of rod 36 extending out of the casing is pivotally connected by a pin 32 to a lever 43 intermediate its ends. One end of lever 43 is connected by a pin at to one end of a link :35, and the opposite end of the link :55 is pivotally connected, by a pin '55, to the casing of the device. The opposite end of lever 33 is operatively connected to the respective governor adjusting rod 22.

Each of the governor control motors 28 further comprises what may be called a Vernier diaphragm 46 preferably of less area than diaphragm 29 and clamped around its edge in the casing and having at one side a pressure chamber 49 which is connected to a pipe 50. At the opposite side of diaphragm 48 is a non-pressure chamber 5| containing a follower 52 engaging the adjacent side of said diaphragm. Projecting from follower 52 is a rod 53 the otuer end of which is pivotally connected to one end of a bell crank 54. The bell crank 54 is pivoted at its knee on a pin 55 carried by an arm 55 projecting from the casing, while the opposite end of said bell trank is connected to pin 42 which connects rod 36 to lever d3. It will be noted that pressure of fluid in the Vernier diaphragm chamber d9 transmitted through bell crank 55 to rod 35 will oppose pressure of fluid in chamber 30 acting on diaphragm 29.

The pressure of regulating spring 4| in each of the governor control motors 28 against the diaphragm 3| is so adjusted by regulating nut 40 as to insure movement of said diaphragm and thereby of the rod 36 and lever $3 to their idling position, in which they are shown in the drawings, and which is defined by contact between the follower plate 38 and a stop 51 in the casing, when pressure of fluid in diaphragm chamber 30 is at a chosen low degree. With the parts thus conditioned, the governor control cam is will assume its idling position in which it is shown in the drawing for thereby conditioning the governor control spring H to permit operation of the engine at idling speed.

When, by operation of the operators control device 33, fluid is provided in diaphragm chamber 30 of each of the governor control motors 28 at a pressure sufiicient to overcome the opposing force of spring 4| plus pressure of fluid in chamber 49 acting on Vernier diaphragm it, the diaphragm 29 will be deflected against said spring to rock lever 43 in a counterclockwise direction for actuating cam 19 to increase the pressure of spring I! in the respective speed governor I0 an amount proportional to the movement of said diaphragm from its normal position and thus proportional to the increase in pressure of fluid provided through the control pipe 32 in diaphragm chamber 35, whereby the speed governor III on the respective engine will operate to correspondingly increase the supply of fuel to the engine. If the pressure of fluid in diaphragm chamber 30 is further increased by the operators control valve device 33 the diaphragm 29 will deflect further to correspondingly increase the pressure of the respective governor spring I! for providing a corresponding increase in the amount of fuel supplied to the engine. On the other hand, to reduce the amount of fuel supplied to the engine, the pressure of fluid in diaphragm chamber 30 will be reduced, by operation of the operators control device 33, to a degree corresponding to the desired reduction in fuel supply, and the regulating spring 4! aided by pressure of fluid in chamber 49 acting on the Vernier diaphragm 48 will then move the diaphragm 29 back to a position in which the pressure of said spring is reduced .a degree corresponding to the reduction in pressure of fluid in chamber 30, whereupon movement of diaphragm 29 will cease. This movement of diaphragm 29 will in turn actuate cam I9 to reduce the pressure of the respective governor control spring l1 whereupon the speed governor I 6 will operate to correspondingly reduce the amount of fuel supplied to the engine. If the pressure of fluid in diaphragm chamber 30 is sufficiently reduced to allow diaphragm 29 to be returned to its idling position by regulating spring M, the governor control cam l9 will be returned to its idling position to thereby permit operation of governor as to reduce the fuel supply to the respective engine to the degree required to permit operation of said engine at idling speed.

In the above described operation of the governor control motors 38 it was assumed that the vernier diaphragm chamber was charged with fluid at some chosen pressure, but the pressure of fluid which may be effective in the Vernier diaphragm chamber 159 of the several motors may be either greater or less than said chosen pressure which will be eifective only on the engine selected as the master for causing equalization of the power output of all of engines, as will be hereinafter described in detail. It is however desired to point out that the position which diaphragm 29 in each of the motors 28 will assume when subject in chamber 3!! to any chosen pressure of fluid will vary in proportion to the pressure of fluid efiective in chamber 49 on the Vernier diaphragm 48. It is further desired to point out that when the Vernier diaphragm 38 in each of the motors 28 is sub- .iect in chamber 29 to fluid at the chosen pressure, which may be twenty-five pounds, the adjusted pressure of regulating spring 4! against the diaphragm 2d will be such that diaphragm 25 will promptly move from its normal or idling position, in which it is shown in the drawing, in response to an increase in pressure in chamber 32 above its normal minimum value.

Associated with each of the engines is a pressure regulating valve device as arranged to be controlled by the respective fuel control shaft 8 for providing in a pipe 6i fluid at a pressure proportional to the position of said shaft and hence proportional to the amount of fuel supplied to the respective engine.

Each of the pressure regulating valve devices 55 comprises (Fig. l) a casing containing two spaced. apart and coaxially arranged flexible diaphragms 52 and 63, of the same areas and clamped around their edges in the casing. Between the two diaphragms 62 and 63. is a chamber 56 open to a fluid pressure supply pipe 65 and thus adapted to be constantly supplied with fluid under pressure. The chamber 5 is formed in two parts separated by a wall 66 but in constant communication with each other through a passage ii? in said wall. At the opposite side of diaphragm 33 is a non-pressure chamber 68 which is open to atmosphere through a breather port 59. At the opposite side of diaphragm 62 is a chamber ZS open through a stabilizing choke ii to a chamber 12 to which pipe Si is connected.

Disposed in chamber 84 between the two diaphragms 62 and 63 is a stem i3 having one end connected to the center of diaphragm 63 by follower plates 75 and a clamping nut E5. The opposite end of stem i3 is in the form of an enlargement 56 extending centrally through the diaphragm 82 and cooperating with a nut '51 in chamber id to secure said stem to diaphragm 82 through the medium of follower plates 18. A coil regulating spring '69 encircling stem 13 in chamber 54 has one end engaging the casing wall 66, while the opposite end acts against the enlargement iii through the medium of a spring follower Bil. With spring '89 fully expanded, the diaphragms E2 and 53 and the stem 13 will assume a position such as that in which they are shown in Fig. 4 of the drawing.

In the stem enlargement I6 is a chamber 3! open through a passage 82 to the fluid pressure supply chamber 64. A fluid pressure supply valve 83 contained in chamber 8! has a fluted stem 84 extending through an axial bore in nut i! into a chamber 85 formed within an extension 8% of said nut. The extension 86 is mounted to slide in a sleeve 31 which extends from the exterior of the casing through chamber #2 and a wall separating said chamber from chamber 1E]. Chamber 85 in the nut extension 36 is open through one or more ports 88 to chamber 12. A spring 89 contained in chamber a! acts on the supply valve 33 for urging it into contact with a seat provided on the nut H.

In chamber 85 the end of the supply valve stem 84% engages a fluid pressure release valve 90 having a fluted stem 9! mounted to slide in a bore provided axially of a plunger 92 which is slidably mounted in sleeve 8? above the nut extension 36, said plunger being provided around the end of said bore which opens to chamber 85 with a seat for engagement by said release valve. The release valve stem 9! extends into a chamber 93 in plunger 92, said chamber being in constant communication with atmosphere through registering ports 5G in said plunger and in the sleeve ill. Chamber 93 contains a bias spring 95 acting on the stem 95. of release valve 98 for urging said valve away from its seat, the pressure of said spring on said release valve stem being less than that of spring 89 on the supply valve 83. The plunger 92 has an annular roove carrying a sealing ring 53 having sliding contact with the interior surface of sleeve 8? for preventing leakage of fluid under pressure from chamber 35 past said plunger to atmosphere.

Outside of the casing and beyond the adjacent end of sleeve $7 is a spring seat 81 secured to plunger 92, and a coil spring 98 encircling said sleeve and supported on the casing bears against said seat for urging said plunger in a direction away from the release valve 98. Above the spring seat 9'! an adjusting screw 99 is connected to plunger 92 by screw-threaded engagement and is locked in an adjusted position by a lock nut We mounted on said screw and engaging the adjacent end of said plunger. The adjusting screw 99 is engaged by one end of a bell crank iii! which at its knee is pivoted on a pin Hi2 carried in an arm I33 projectin from the casing. The opposite end of the bell crank [ill is operatively connected to one end of a link I84 the opposite end of which is connected to one end of an arm 985 which is mounted on the respective engine fuel control shaft 3 for movement therewith.

With the fuel control shaft 8 On each engine in its engine idling position, screw 59 in the respective regulating valve device Gil will be turned out of plunger 92 for urging said plunger in a downwardly direction against springs 98 and 95 to a position in which said plunger may contact the release valve 93, with the supply valve 83 seated by spring 58 and with the spring 19 fully expanded. The screw 99 may then be locked to the plunger 52 by the lock nut I00. If the fuel control shaft 8 on either engine is now rocked out of its idling position (Fig. 1 and 2) this movement will actuate arm Hi5 and link M4 to rock bell crank IEH of the respective pressure regulating device 68 in a corresponding direction and move plunger 92 in the direction of the supply valve 83, and with the release valve 90 seated against the end of said plunger,

said supply valve will be opened to permit flow of fluid under pressure from chamber 64 to chamber 85 and thence through port 88 to chamber l2 and the respective pipe 6|. At the same time as fluid thus flows to pipe 6| it will equalize through the stabilizing choke II into chamber I and therein act on diaphragm 62 in opposition to pressure of the regulating spring I9.

When the pressure of fluid then supplied to chamber 16 becomes increased to a degree suflicient to overcome the force of regulating spring 19, the diaphragms 62 and 63 will deflect against said spring. Now assuming that movement of the respective fuel control shaft 8 has ceased in some position out of its idling position, movement of plunger 92 and thereby of the release valve 9% and supply valve 83 will also have stopped in a corresponding position, as a result of which, deflection of diaphragms 62 and 63 by increasing pressure of fluid in chamber will be relative to said supply valve until said supply valve becomes seated. Seating of the supply valve 83 will then prevent further flow of fluid under pressure to chambers I2 and I0 and to pipe 6i whereupon deflection of diaphragms 62 and 63 will cease, since the pressure of the regulating spring '59 will have been increased sufficiently to counterbalance the pressure of fluid in chamber Ill. The .increase in pressure of fluid in pipe 6 I will therefore be limited to a degree depending upon the extent of movement of the respective fuel control shaft 8 out of its idling position.

If the fuel control shaft 8 on either engine is turned further out of its idling position the respective pressure regulating valve device 60 will again be operated to increase the pressure of fluid in the respective pipe 6| to a degree corresponding to such movement. A maximum pressure of fluid will be obtained in each pipe 6I when the respective fuel control shaft 8 is moved to its full fuel position indicated by the dot-dash line 9.

On the other hand, if the fuel control shaft 8 on either engine is turned in the direction of its idling position, assuming that it is out of said position, this movement will, in the respective pressure regulating device 60, rock bell crank WI to permit movement of plunger 92 by spring 98, plus pressure of fluid in chamber 85 acting on said plunger, in a direction away from the supply valve 83. With the supply valve 83 seated and stationary at this time due to pressure of fluid in chamber I6 counterbalancing the pressure of regulating spring I9 on diaphragm 62, the release valve spring 95 will hold the release valve 98 stationary with the supply valve 83 and against movement with plunger 92, so that this movement of said plunger will be away from said release valve to thereby open communication past said release valve for releasing fluid under pressure from chamber I2 and pipe 6i and also from chamber 10 above diaphragm 62 by way of stabilizing choke II. As the pressure of fluid in chamber 76 is thus reduced the regulating spring I9 will deflect diaphragms 62 and 63 in the direction of plunger 92, and during such movement spring 89 will move the supply valve 83 and the release valve 98 along with said diaphragms. Assuming that the fuel control shaft 8 is now stopped in a position out of idling position, movement of plunger 92 will cease in a corresponding position, so that movement of the release valve 96 with the diaphragms 62 and 63 will then be relative to said plunger until said valve engages its seat for preventing further release of fluid under pressure from chamber 72, pipe BI and chamber I0. When the release valve is thus closed, preventing further release of fluid under pressure from chamber ID, the diaphragms 62 and 63 will stop moving since the pressure of fluid in said chamber will just counterbalance the pressure of regulating spring I9. Thus the pressure of fluid in pipe 6I will only be reduced to a degree corresponding to the position of the fuel control shaft 8 out of idling position.

If either fuel control shaft 8 is moved further toward but not completely to its idling position the respective regulating valve device 66 will again operate as just'des'cribed to effect a corresponding reduction in pressure of fluid in the respective pipe 6|, while if said shaft is returned to its idling position the parts of said regulating valve device will return to the position shown in' Fig. 4 in which the release valve 96 will just contact its seat at the time the pressure of fluid in said pipe and in chamber 19 becomes reduced to substantially atmospheric pressure and the regu1ating spring 79 becomes fully expanded.

It will now be seen that the regulating valve device 66 on each engine will operate to provide in the respective pipe 6! a pressure proportional to the position of the respective fuel control shaft 8, and hence proportional to the amount of fuel supplied to said engine, and it is desired to point out that the regulating valve devices 66 on all of the engines will be initially adjusted the same, so as to provide the same pressures in the respective pipe 6! for the same positions of the respective fuel control shafts 8.

Associated with each of the engines is an equalizing valve device IIB which comprises a casing containing two coaxially arranged and spaced apart flexible diaphragms III and H2 of the same areas, which are clamped around their edges in their casing. Between the two diaphragms is a chamber H3 adapted to be constantly supplied with fluid under pressure through a fluid pressure supply pipe H4. The chamber I I3 is formed in two parts divided by a wall H5 having a passage H6 connecting said parts so that the adjacent faces of the diaphragms III and H2 will be constantly subject to fluid at supply pressure. At the opposite face of the diaphragm H2 is a control chamber I I! which is open to pipe 6! leading to the respective pressure regulating valve device 66. At the opposite face of diaphragm I I I is a control chamber H8 which is open to a pipe H9. The pipes H9 at the several engines are all connected to an equalizing pipe I26 which extends to all of said engines.

Each equalizing valve device further comprises a stem iZI extending through chamber I I3 and the chamber dividing wall I I5 and having one end clamped to the center of diaphragm H2 by follower plates I22 and a clamping nut I23. The opposite end of stem I2l is connected to the center of diaphragm II I by follower plates I24 and a clamping nut I25 disposed in chamber H8 and connected to said stem. The casing of the device also has a chamber 526 connected to a pipe I21 and separated from chamber II 8 by a wall I28, and extending from the exterior of the casing through chamber I26 and wall I28 and having one end open to chamber H8 is a bushing I29 arranged in coaxial relation with the diaphragms III and [I2 and with the nut I25. The nut I25 has a cylindrical extension I30 slidably mounted in an axial bore provided in the adjacent end or" bushing I29, and encircling and having sealing and sliding contact with said extension is a sealing ring I37: carried in a groove in said bushing. The interior of the extension I35 is open to a chamber I32 formed within the bushing I29 and said chamber is open through one or more ports I33 to the casing chamber I25.

One end of chamber I32 within the bushing I25 is closed by a nut I34 secured to said bushing. Secured in the nut I34 is an element I35 having a bore arranged in coaxial relation to the flexible diaphragms III and H2, and in said bore is slidably mounted a pin I36. The pin I36 is provided on the end disposed in chamber I32 with a head I37, while on the opposite end of said pin is a fluid pressure release valve I38 arranged to cooperate with a seat on nut I34 for controlling communication between a passage I39 extending along one side of element I35 to chamber I32, and a passage I4 3 which leads to atmosphere. interposed between the nut I34 and the stem head I3? is a spring I41 for moving the release valve I38 out of contact with its seat.

A pin I42 projects from the release valve stem head I31 centrally through teh cylindrical extension I35 of nut I25 and thence through an opening I23 in said nut to engage a fluid pressure supply valve I44 which is contained in a chamber Hi formed within said nut. The nut I25 has a seat for the release valve I44 around the opening I43, which opening is of greater diameter than stem I42. lhe supply valve I44 is provided on one end of a fluted stem I46 which is mounted to slide in a bore extending through the nut I25 to chamber it? formed below said nut the diaphragm connecting stem I2I. The chamber I41 is connected through one or more ports I43 to the fluid pressure supply chamber H3 between the two diaphragms III and H2. in chamber It? the supply valve stem I45 is provided with a head I49 against which acts one end of a coil spring I55 the opposite end of which is supported by a wall in stem I2 I. A coil spring I5! contained in chamber II'I acts on the adjacent diaphragm follower plate I22 for opposing movement or" the diaphragms III and H2 and thereby of nut I25 in a direction against said spring.

In each equalizing valve device IIIJ it will now be noted that diaphragm H2 is adapted to be subjected in chamber I I? to pressure of fluid provii" by the respective pressure regulating do e through the connecting pipe GI, while diaphragm III is adapted to be subjected in chamber I I to pressure of fluid in the equalizing pipe I25. It will further be noted that spring acting to seat the supply valve I44 will oppose movement of the diaphragms III and H2 and the connecting stem I2I by an increase in pressure of fluid in chamber In over that efiective in chamber II8, while spring I5I will oppose movement of said diaphragms and stem in the opposite direction by a preponderate pressure of fluid in chamber H8. The springs I55 and I5I are so proportioned as to require a definite or fixed difierential such as t; of a pound, between the fluid pressures in chambers II? and H8, acting in either one direction or in the opposite direction, to move the diaphragms and the connecting stem IEI, and this diiierential will be the same regardless of the pressure of fluid which may be eiiective in said chambers.

valve i The opposing forces of springs I and I5! on diaphragms III and II2 and the connecting stem I2I is also adapted to insure movement of these parts to a neutral or lap position in which both the supply valve I44 and the release valve I38 are seated, as shown in the drawing, when the differential between the pressures of fluidv in chambers II! and H8 is less than the chosen differential, above mentioned.

Also associated with each of the engines is a selector valve device I52 for selectively conditioning the respective engine either to act as .naster to which the power output of all of the other engines will be equalized, or for subjugating said engine to control from another selected master engine.

Each selector valve device comprises a casing to which is connected pipe 55 from the vernier diaphragm chamber 49 in the respective governor control motor 23, pipe i2! from the respective equalizing valve device III the equalizing pipe I25, and a pipe 53 which is adapted to be charged with fluid at a chosen fixed pressure such as 25 pounds by operation of a suitable fluid pressure reducing valve device I55.

Each of the selector valve devices I52 further comprises valve means, which may be in the form of plug valve I55, and a handle I55 for turning said valve to either a master position in which these parts are shown on engine A or to a slave position in which said parts are shown on engine B. The plug valve I55 has two oppositely arranged cavities id! and I53 and a through port I59 arranged between said cavities. In the master position of the valve operating handle I55 and valve I55 the cavity i5? will connect the equalizing pipe I25 to pipe I2? leading to the equalizing valve device IIII on the respective engine, and cavity I53 will connect pipe I53 to pipe 55 leading to the respective governor control motor 23, while port I55 performs no function. In the slave position of plug valve I55 the port I59 will establish communication between pipe 55 from the respective governor control motor 28 and pipe IZ'I leading to the respective equalizing valve device I55, while the ends of the respective pipes I25 and I53 will be closed by said valve.

Operation In operation, let it be assumed that by operation of the operators control device 33 the pressure of fluid in pipe 32 and thereby in diaphragm chambers 35 in the governor control motors 28 on the several engines is reduced to a degree to permit the parts of said motors to assume idling positi as shown in Fig. 3 of the drawings, to thereby position the respective governor cams Is in their idling position, as shown in Fig. 2 of the drawing.

Let it further be assumed that the engines have been started and are operating at idling speed, as selected by the operators control device 33, under which condition the parts of the fuel control system on each engine will assume the position in which these parts are shown in Fig. 2 of the drawing.

With the engines operating at idling speed the pressure regulating devices SIS will be so adjusted by the respective fuel control shafts that at each engine the pressure of fluid in pipe EI and thereby in diaphragm chamber I II of the equalizing valve device I It at that engine will be at substantially atmospheric pressure.

Let it further be assumed that pipe I53 extend- 1 1 ing to all of the engines is charged with fluid at the chosen pressure, of for instance 25 pounds, by operation of the reducing valve device I54, and that engine A is selected as the master engine, against which the power output of the other or slave engine or engines will be matched. With engine A selected as the master engine the selector valve device I52 thereon will be turned to its master position, while on the slave engine B the sol ctor valve device 552 will be turned to its slave position. With the selector valve device I52 on the master engine in its master position opening pipe I53 to pipe t fluid at the chosen pressure provided in the former pipe will equalize into the Vernier diaphragm chamber 49 of the respective governor control motor 28 but will have no effect upon the operation or positioning of the parts of said motor at this time since the master diaphragm 2 t erein is already in its idling position against the stop 5?; it being noted that such pressure acts to move said diaphragm against said stop. With the selector valve device I 52 on the master engine A in its master position the equalizing pipe I23 will be open to pipe I21 and thus to chamber I28 in the respective equalizing valve device Iiil. Pipe I2!) is also open at all times through pipe I59 to chamber H8 in the equalizing valve device III).

Let it also be assumed that the equalizing pipe iii} is initially at atmospheric pressure, like pipe ti on master engine A, as a result of which, chambers I is and H? in the equalizing valve device lie on said engine will both be at substantially atmospheric pressure, so that springs I50 and I5I in said device will hold the parts thereof in their neutral position in which the respective supply valve I42 and release valve I38 are both closed as shown in Fig. 5.

On slave engine B the parts of the equalizing valve device 5 It will also be in their neutral position with the equalizing pipe i and the respective pipe 6i both at substantially atmospheric pressure. On the slave engine the Vernier diaphragm chamber ts in the respective governor control motor 28 is open through pipe 50 and port I59 in the respective selector valve device I52 to pipe I2! leading to the respective equalizing valve device Iii and let it be assumed that these pipes and chamber are also initially at atmospheric pressure. With the Vernier diaphragm chamber 59 in the governor control motor 28 on slave engine B at atmospheric pressure the diaphragm 2a in said motor will also occupy its idling position under pressure of regulating spring ll the same as if said chamber were charged with fluid as on the master engine A. Thus when the engines are operating at idling speed the supply of fuel thereto will be limited by the position of diaphragms as defined by contact with stops 5'! in the resepective governor control motors 28.

to operate the engines at a speed in excess of idling and to accomplish this operates the control valve device 33 to provide in pipe 32 and thereby in diaphragm chamber 33 of each of the governor control motors 28 fluid at a pressure which on master engine A will deflect the diaphragm 29 out of its idling position and thus out of contact with stop 51 against the opposin force of spring AI and the chosen fixed pressure of fluid acting in the respective Vernier diaphragm chamber 48. Since on slave engine B there is initially no pressure in the Vernier diaphragm chamber 49 of the respective governor control motor 28, the pressure of fluid provided in the respective diaphragm cham- Now let it be assumed that the operator desires -12 ber 30 will deflect diaphragm 29 away from stop 51 to a greater extent than occurs on master engine A and as a result the governor control cam I9 on the slave engine will be turned out of idling position to a greater extent than on the master engine. As a result the speed governor II) on slave engine B will tend to cause operation of the respective fuel control shaft 8 to supply a greater amount of fuel to said engine than is obtained on master engine A by operation of the respective speed governor.

As the fuel control shafts 8 on the two engines are thus operated to increase the supply of fuel thereto, the respective pressure regulating valve devices 60 will be operated to increase in proportion the pressure of fluid in diaphragm chambers II! of the respective equalizing valve devices H0. On master engine A the equalizing valve device III] will be operated by the pressure of fluid thus provided in chamber II'I' against the pressure of spring- I50 to move nut I25 out of seating engagement with the supply valve M4, which will be held against movement at this time since the release valve I38 will be in contact with its seat. When the supply valve I44 on the master engine is thus opened fluid under pressure will flow from chamber H3 between the diaphragms III and I I2 past said valve to chamber I32 and thence to chamber I26 and from the latter chamber through pipe I 21, and cavity I5? in the respective selector valve device I52 to the equalizing pipe I26 leading to the equalizing valve devices I In on the several engines. On the master engine, the pressure of fluid thus provided in equalizing pipe I20 will flow back through pipe I I9 to chamber I I3 in the respective equalizing valve device and therein act on diaphragm III in opposition to the pressure of fluid in chamber H1 acting on diaphragm I I2. When the pressure of fluid obtained in equalizing pipe I28 and acting in chamber II8 of the equalizing valve device I IE! on the master engine then becomes increased by flow past the respective supply valve I44 to substantially the same degree as the opposing pressure of fluid in chamber I I! the respective spring I50 will move the diaphragms III and 2 against the pressure of fluid in chamber II! and relative to the supply valve I44 until the nut I25 seats against said valve to prevent further flow of fluid under pressure to the equalizing pipe I 20 and thereby to diaphragm chamber IIB. It will be noted that spring I5!) in the equalizing valve device III) on master engine A insures closing of the respective supply valve I 45 before the pressure of fluid in the equalizing pipe I20 and in the respective diaphragm chamber H8 exceeds that in diaphragm chamber I H, but permits the pressure in said pipe to increase to substantially that provided by the respective regulating valve device 60 to pipe GI and it will further be noted that this pressure in the equalizing pipe I20 will be proportional to the extent of movement of the fuel control shaft 8 on master engine A out of its engine idling position, and therefore proportional to the amount of fuel supplied to master engine A.

On slave engine B the pressure of fluid provided in the equalizing pipe I20 as above described will be effective in diaphragm chamber H8 of the respective equalizing valve device III while in chamber II 1 of said device there will be fluid at a pressure controlled by the respective regulating valve device 60 and therefore proportional to the extent of movement of the respective fuel control shaft 8 from its idling position. On the slave engine the fuel control shaft 8 will be initially moved from idling position to a greater degree than on the master engine, since it was assumed that initially the Vernier diaphragm chamber 49 of the respective governor control motor 28 was at atmospheric pressure, and as a result, the pressure of fluid obtained in chamber II! of the respective equalizing valve device I It will therefore be greater than the opposing pressure in chamber II8 obtained from the equalizing pipe I20. As a result, on the slave engine B the diaphragrns I! I and H2 in the equalizing valve device III) will move against spring I50 and unseat the nut I25 from supply valve I44 to permit fluid under pressure to flow from chamber I I3 to chamber I26 and thence through pipe I27, port I59 in the respective selector valve device I52 and pipe 50 t the Vernier diaphragm chamber :19 in the governor control motor 28 on the slave engine. As the pressure of fluid in the Vernier diaphragm chamber 49 of the governor control motor 28 on the slave engine then increases such pressure will act through bell crank 54 and rod 36, in conjunction with the pressure of regulating spring II, to oppose the pre-selected pressure of fluid provided in the diaphragm chamber 39, and since the diaphragm 29 was initially moved against said spring to a position determined solely by the pressure in diaphragm chamber 38, the pressure of fluid now provided in Vernier chamber 49 will move the diaphragm 29 back in the direction of stop 51. This movement of diaphragm 29 and thereby of stem 26 in the motor 28 on the slave engine will in turn actuate lever 53 to turn the respective governor control cam I9 in a direction to reduce the pressure of spring I'I, whereupon the respective governor It will operate to correspondingly turn the fuel control shaft 8 on the slave engine for reducing the supply of fuel to said engine.

As the fuel control shaft 8 on the slave engine is thus operated to reduce the supply of fuel to said engine, the respective pressure regulating valve device 65 will operate to correspondingly reduce the pressure of fluid in diaphragm chamber I I? of the respective equalizing valve device H9, and this operation of supplying fluid to the Vernier diaphragm chamber 19 of the respective governor control motor 28 for reducing the supply of fuel to the slave engine, and of reducing the pressure of fluid in diaphragm chamber H? of the respective equalizing valve device I II], will continue until said pressure becomes reduced to substantially that effective in equalizing pipe I26 and therefore in chamber IE8 of said equalizing valve device. When the pressure of fluid in. chamber i I! of the equalizing valve device Iii on the slave engine finally becomes reduced to substantially that acting in chamber H3 and in the equalizing pipe I20, spring I59 will move diaphragms H2 and I I I and thereby nut I25 downwardly, as viewed in Fig. 5, until said nut seats against the supply valve I44 for preventing further flow of fluid under pressure to the Vernier diaphragm chamber 49 in the respective governor control motor 28. Operation of the governor control motor 28 on the slave engine to reduce the supply of fuel to said engine will then cease, in a position it will be noted, in which the pressure of fluid provided by the respective regulating valve device '3 in diaphragm chamber I I! of the respective equalizing valve device H8 equals substantially that pro- Vided in equalizing pipe I28 by operation of the regulating valve device 6% on master engine A, and since the pressure of fluid provided by both of these regulating valve devices is proportional to the amount of fuel supplied to the respective engines the supply of fuel to slave engine B, under the condition above described, will therefore be reduced to substantially the same amount as being supplied to master engine A, whereby the power output of the slave engine will be substantially equalized with that of the master engine.

With the engines operating at a chosen equalized speed or degree of power output as just described, let it be assumed that the operator desires to increase the power output of said engines, and to accomplish this, operates the control valve device 33 to increase the pressure of fluid in the control pipe 32. The governor control motor 28 on master engine A will then operate to cause operation of the respective governor I6 and fuel control shaft 8 to increase the fuel supply to said engine to an amount proportional to the increase in pressure of fluid in diaphragm chamber 3% regardless of the constant pressure of fluid effective in Vernier diaphragm chamber 49 of the respective governor control motor 28, and operation of the fuel control shaft 3 on said engine will also operate the respective pressure regulating valve device 68- to provide through pipe 6% in diaphragm chamber II'I of the equalizing valve device Ilil on the master engine fluid at a pressure proportional to the increase in fuel supply to the engine. The equalizing valve device III on the master engine 8 will then operate to provide in the equalizing pipe 129 fluid at a pressure also proportional to the amount of fuel supplied to the master engine A, as hereinbefore described.

If in response to this operation of the operators control device 33 to increase the power output of the engines, the governor control motor 8 and the governor III on slave engine 33 should cause operation of the respective fuel control shaft 5 to supply more fuel to the slave engine than is being supplied to the master engine, the pressure regulating valve device St on the slave engine will be operated to supply to the respective equalizing valve device IIB fluid at a pressure greater than in the equalizing pipe I20 and said equalizing valve device will then operate to cause operation of the respective governor control motor 28 to reduce the amount of fuel supplied to the slave engine to substantially the same degree as being supplied to the master engine, in the same manner as hereinbefore described.

l/Vhen the operators control device 33 is operated to increase the power output of the engine let it be assumed however that the increase in fuel supply to the slave engine B is less than to master engine A. Under this condition the pressure of fluid provided by the regulating valve device 66 on the slave engine through pipe SI in chamber II! of the respective equalizing valve device I Iii will be less than provided the equalizing pipe 429 and in diaphragm chamber N8 of said equalizing valve device, so the pressure of fluid in the latter chamber will move the diaphragms III and H2 and thereby the nut I25 against spring i5l. The supply valve IM will move with the nut I25 and as a result draw the stem I42 in a direction away from the release valve stem head I31 which will permit spring MI to unseat the release valve I35.

When the release valve I38 in the equalizing valve device I It on the slave engine is thus opened fluid under pressure will be released from the vernier diaphragm chamber 59 in the governor control motor on said engine and the consequent reduction in pressure in said chamber will permit pressure of fluid in diaphragm chamber 30 acting on diaphragm 29 to deflect said diaphragm further in a direction away from stop 51 to cause the respective governor E to change the position of the respective fuel control shaft 3 for correspondingly increasing the supply of fuel to said engine, and for operating the pressure regulating valve device 60 on said engine to correspondingly increase the pressure of fluid in chamber ll! of the respective equalizing valve device H0. This operation of the governor control motor 28, incident to release of fluid under pressure from the Vernier diaphragm chamber 59, and of governor l0, fuel control shaft 8 and pressure regulating valve device as on the slave engine will continue until the pressure of fluid provided by said regulating valve device in chamber ill of the respective equalizing valve device l lil is increased to substantially the same degree as acting in chamber H8, whereupon spring i! will move diaphragm l i! and H2 in an upwardly direction and thereby actuate spring I59 and the seated supply valve M4 to move the release valve I38 into contact with its seat to prevent further reduction in the pressure of fluid in the respective Vernier diaphragm chamber 89, and to in turn prevent further increase in the supply of fuel to the slave engine.

In the operation just described it Will be noted that the position of the fuel control shaft 8 on the slave engine will change for increasing the supply of fuel to said engine until the pressure of fluid delivered by the respective regulating valve device 6!) is increased to substantially that provided in the equalizing pipe H28 by the regulating valve device 6!! on the master engine A, and since the amount of fuel supplied to the engines is proportional to the pressure delivered by the respective pressure regulating valve devices 60, substantially the same amount of fuel will now be supplied to slave engine B as is being supplied to master engine A.

With the engines operating at a chosen degree of power output the operator may desire to reduce the output of the engines, and to accomplish this will operate the control valve device 33 to reduce the pressure of fluid in control pipe 32 and thereby in diaphragm chambers 30 of the governor con-' trol motors 28 on the several engines. On the master engine A the diaphragm 29 will then be deflected by the regulating spring ll and the pressure of fluid in the vernier diaphragm chamber 49 to a new position, corresponding to the reduction in pressure of fluid in chamber 30, and thereby cause governor H? on said engine to correspondingly change the position of the fuel control shaft 8. As the position of the fuel control shaft 8 on the master engine is thus changed the supply of fuel to the master engine will be correspondingly reduced and the respective pressure regulating valve device 59 Will be operated to reduce the pressure of fluid in diaphragm chamber ll! of the respective equalizing valve device H0 in proportion to the change in position of said fuel control shaft and the reduction in fuel supplied to said engine. When the pressure of fluid in chamber l H of equalizing valve device H0 on the master engine is thus reduced, said device will in turn operate to reduce the pressure of fluid in the equalizing pipe l 26 to substantially that effective in chamber H! and hence in proportion to the reduction in fuel supply to the master engine.

When the pressure in chamber 36 of the governor control motor 28 on the slave engine B is reduced as above described, said motor will also operate to reduce the supply of fuel to said engine, in accordance with the reduction in pressure in said chamber, but if for any reason the amount of fuel should be reduced to a degree less than provided on master engine A, the pressure of fluid in chamber ll! of the respective equalizing valve device Hi3 will become reduced by the respective regulating valve device 69 to a degree below that provided in chambenlla of said device from the equalizing pipe I225. The equalizing valve device H0 on the slave engine will then be operated to reduce the pressure of fluid in the vernier diaphragm chamber as of the respective governor control motor 28 until the respective governor 16 causes the fuel control shaft 8 to obtain a new position in which the respective pressure regulating valve device 69 provides fluid in chamber Ill of the respective equalizing valve device H0 at a pressure substantially equal to that in the equalizing pipe 20. When this condition is obtained the equalizing valve device M0 on the slave engine will operate to prevent further release of fluid under pressure from the Vernier diaphragm chamber 49 of the respective governor control motor 28 for stopping operation of said motor, in a position, it will be noted, in which the fuel control shaft 8 on and thereby the amount of fuel supplied to the slave engine will correspond substantially to the position of the fuel shaft and the supply of fuel to the master engine A.

If, when the fuel supply to the master engine is reduced a less reduction occurs on the slave engine, then the equalizing valve device I In on the slave engine will be operated by pressure of fluid from the respective pressure regulating valve device 68 to increase the pressure of fluid in the respective Vernier diaphragm chamber 49 for reducing the supply of fuel to the slave engine, until the pressure of fluid delivered by said regulating valve device corresponds substantially to that provided in the equalizing pipe [28, at which time the fuel supply to the slave engine will substantially equal that to the master engine, as will be apparent without further description.

From the above description it will now be noted that the pressure of fluid in Vernier diaphragm chamber 49 of the governor control motor 28 on the slave engine may be either greater or less than that in the corresponding chamber on the master engine at the time the power output of the slave engine is equalized with that of the master engine. The provision of a fixed constantly maintained pressure in the Vernier diaphragm chamber 49 of the governor control motor 28 on the master engine thus provides a standard with respect to power output of the respective engine against which the power output of the slave engine is measured or to which it is equalized.

By reversing the positions of the selector valve devices I52 on the master and slave engines A and B, respectively, the equalizing valve device I l 0 on engine B will be rendered effective to govern the pressure in the equalizing pipe I20 while the apparatus on engine A will then automatically operate to equalize the power output of engine A to that of engine B, as will be evident without further description. In other words, either of the two engines may be selected as the master engine, and if the system embodied more than two engines any one of the engines of the system could be used as the master engine for controlling the others.

selector valve device I52 at the selected engine can either render it the master engine or controllable from another selected master engine.

Further in connection with the equalizing valve The mere turning of the.

devices H3, it will be noted that the springs 15!] and lei not only insure movement of the diaphragms l i2 and 1 it to neutral position in which both the supply valve I44 and the release valve I38 are closed, but also prevent said parts over traveling neutral position, since said springs insure that neutral position will be obtained without increasing pressure of fluid in chamber H8 over that in chamber Ill on the one hand, or without reducing the pressure of fluid in chamber ilB below that in chamber Ill, on the other hand. Due to this, operation of the governor control motor 28 and of governor ID on the slave engine to effect movement of the respective fuel control shaft 8 in a direction to increase the supply of fuel to said engine will be positively stopped when the pressure of fluid delivered by the regulating valve device 6!] on said engine may substantially equal but does not exceed that delivered by the pressure regulating valve device on the master engine, so that there will be no oversupply of fuel to the slave engine with respect to that supplied to the master engine. Further, when the fuel shaft 8 on the slave engine is operated to reduce the supply of fuel to said engine the supply will not be reduced to below that to the master engine since the equalizing valve device ill on the slave engine will obtain its neutral position to stop movement of the respective fuel control shaft 8 when the pressure of fluid in diaphragm chamber Ill becomes reduced by operation of the respective pressure regulating valve device 60 to substantially but not below that provided by the regulating valve device so on the master engine. The springs I50 and 55! in thus preventing operation of the equalizing valve device i it on the slave engine to cause an oversupply, or an undersupply, as the case may be, of fuel to the slave engine with respect to that being supplied to the master engine renders the whole apparatus stable and positive in operation.

Moreover the governor ID and other parts of the control apparatus on each engine are so designed that said governor will operate the respective pressure regulating valve device 66 to vary the pressure of fluid in chamber H! of the respective equalizing valve device H9 at least in unison with operation of the'governor control motor 28 to effect change in adjustment of said motor, in order that on the slave engine operation of said motor and change in adjustment of the respective governor is and fuel control shaft 8 will cease substantially at the instant the respective equalizing valve device I It is moved into its neutral position. The fuel control shaft 8 on the slave engine will therefore be positively stopped a position corresponding substantially to that of the fuel control shaft 8 on the master engine as determined by the pressure of fluid in the equalizing pipe 82%, so as to ensure that the amount of fuel supplied to the slave engine will be limited to substantially the same amount as supplied to the master engine.

It is desired to further point out that the sensitivity of the equalizing valve device I ill on each engine remains the same throughout the full fuel control range of the respective fuel control shaft 3, that is, regardless of the opposing pressures of fluid which may be acting in chambers I I1 and H8, since operation of said device depends only upon a chosen differential between said opposing pressures, and this is very desirable in that it will insure as prompt equalization of the power output of the slave engine to that of the master 18 engine when the engines are operating against a maximum load, as when operating at idling speed and possibly under no load.

Summary It will now be seen that the improved control apparatus provides positive automative equalization of the amount of fuel supplied to each of any desired number of slave engines with the amount of fuel supplied to a preselected master engine, so as to substantially equalize the power output of the several engines, which is particularly desirable where several engines are connected to a common load in order to substantially equally divide the load between the engines.

It will be further noted that any one of the engines can be employed as the master engine merely by turning the selector valve device I52 on that engine to its master position, while leaving the selector valve device 552 on the other engine or engines in its slave position.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1. A control apparatus for equalizing the power output of two prime movers comprising an equalizing pipe extending to both of prime movers, and further comprising for each prime mover, fluid pressure controlled power control means for adjusting the power output of the respective prime mover in proportion to the pressure of such fluid, pressure regulating me is adjustable in accordance with operation of said power control means for supplying fluid at a pressure pro ortional to the power output of said prime mo equalizing means controlled by opposing pre es of fluid in said equalizing pipe and sup lied by pressure regulating means and opera -le by a preponderance in pressure provided by said regu lating means over that in said equalizing to supply fluid under pressure to another pipe, and operable by a preponderance in pressure in said equalizing pipe over that provided by pressure regulating means to release fluid under pressure from said other pipe, '"l operable to bottle up the fluid pressure in or 1" ce upon equalization of said opposi a two position selector device 11 ing o for connecting said equalizing pipe and for also providing controlled power control means flu.- pressure, and having another pc connecting said equalizing e from pipe and for connecting sai other pipe to said fluid pressure controlled means.

2. A control apparatus for power output of two prime movers comp? equalizing pipe extending to both 0? movers, and further comp "lg for each mover, fluid pressure con rolled power con means for adjusting the power output oi the spective prime mover in prop rtion the pressure of such fluid, pressure regulating means adjustable in accordance with operation of s or power control means for supplying fluid at a pressure proportional to the per. er output of said prime mover, movable power means subject to pressure of fluid in said equalizing pipe acting in opposition to pressure of fluid supplied by said pressure regulating means movable to one position by the pressure of fluid supplied by said regulating means when it exceeds that said equalizing pipe, to a second position by pressure of fluid in said equalizing pipe when it exceeds that provided by said pressure regulating means, and to a neutral position upon equalization of pressures of fluid in said equalizing pipe and supplied by said regulating means, valve means operable by said movable power means in said one position to supply fluid under pr ssure to another pipe, in said second positi to release fluid under pressure from said ot or pipe and in said neutral position to bottle up the fluid pressure in said other pipe, a source of fluid at a chosen pressure, and a two position selector device operable in one of said two positions to establish two fluid pressure communications one between said other pipe and said equalizing pipe and a second between said source of fluid and said fluid pressure controlled power control means and operable in the other of said two positions to close said communications and to establish a communication between said other pipe and said fluid pressure controlled power control means.

3. A control apparatus for equalizing the power output of two prime movers comprising an equalizing pipe extending to both of said prime movers, a constant pressure pipe extending to both of said prime movers, and valve means for maintaining said constant pressure pipe charged with fluid at a chosen pressure, said apparatus further comprising for each prime mover fluid pressure controlled power control means for varying the power output of said prime mover in proportion to the pressure of such fluid, pressure regulating means adjustable in accordance with operation of said power control means for supplying fluid at a pressure proportional to the power output of said prime mover, equalizing means subject to pressure of fluid in said equalizing pipe acting in opposition to pressure of fluid supplied by said regulating means and movable to one position by pressure of fluid supplied by said regulating means when it exceeds that in said equalizing pipe, and to a second position by pressure of fluid in said equalizing pipe when it exceeds that provided by said regulating means, spring means included in said equalizing means for opposing movement thereof by fluid under pressure to said one and second positions and for moving said equalizing means to a neutral position upon substantial equalization of the pressures in said equalizing pipe and supplied by said pressure regulating means, valve means operable by said equalizing means in said one position to supply fluid under pressure to a third pipe, in said second position to release fluid under pressure from said third pipe and in said neutral position to bottle up the fluid pressure in said third pipe, and a selector device having one position for establishing two communications one between said third pipe and said equalizing pipe and a second between said constant pressure pipe and said fluid pressure controlled power control means, said selector device having a second position for closing said communications and for establishing a communication between said third pipe and said fluid pressure controlled power control means.

4. A control apparatus for equalizing the power output of two prime movers comprising a fluid pressure equalizing pipe extending between said prime movers, a power output regulating pipe for said prime movers, an operators control device for varying pressure of fluid in said regulating pipe, and a source of fluid at constant pressure at both prime movers, said apparatus further comprising for each prime mover an fluid in said regulating pipe, and secondary fluid pressure control means, and means controlled by said primary and secondary means for ad-' justing said power control element in accordance with cooperative eflect of pressures of fluid on said primary and secondary means, a fluid pressure regulating device operable by said power control element to provide fluid at a pressure proportional to the power output of said prime mover, equalizing means subject to pressure of fluid provided by said pressure regulating device and in said equalizing pipe and operable by pressure provided by said regulating device when it exceeds that in said equalizing pipe to supply fluid under pressure to another pipe, and operable by pressure of fluid in said equalizing pipe when it exceeds that provided by said pressure regulating device to release fluid under pressure from said other pipe and operable to bottle up fluid pressure in said other pipe upon equalization of pressure in said equalizing pipe with that provided by said pressure regulating device, and a selector device at each prime mover having one position for subjecting said secondary means to pressure of fluid in said source and for at the same time establishing communication between said other pipe and said equalizing pipe, and having a second position for closing said communication and for at the same time subjecting said secondary means to pressure of fluid in said other pipe.

5. A control system for equalizing the power output of a plurality of prime movers comprising an equalizing pipe extending to all of said prime movers, power control means for each prime mover, a fluid pressure controlled motor for each prime mover operable to eiTect opera tion of the respective power control means to vary the power output of the prime mover in proportion to the pressure of controlling fluid, fluid pressure regulating means for each prime mover operable by the respective power control means to provide fluid at a pressure proportional to the power output of the respective prime mover, and means at each prime mover including a selector valve having a master control position for providing a chosen pressure of fluid in the respective fluid pressure motor and for at the same time rendering the pressure of fluid in said equalizing pipe variable in accordance with variations in pressure of fluid delivered by the respective fluid pressure regulating means, and having a second position for rendering pressure of controlling fluid in the respective motor variable in accordance with the difierential between the pressures in said equalizing pipe and delivered by the respective pres-sure regulating means.

ARTHUR G. LARSON.

REFERENCES CITED The following references are of record in the flle of this patent;

UNITED STATES PATENTS 

